Oscilloscope Reference Measurement warnings
When samples are out of range, the measurement will give a warning to that effect (for example,
CLIPPING) if the measurement could change by extending the measurement range slightly. The
algorithms as
sume the samples recover from an overdrive condition instantaneously.
For example, if MidRef is set directly, then MidRef would not change even if samples were out of range.
However, if M
idRef was chosen using the % choice from the Set Levels in % Units selection of the
Measure menu, then MidRef could give a CLIPPING warning.
NOTE. When measurements are d isplayed using Snapshot, out of range warnings are NOT available.
However, if you question the validity of any measurement in the snapshot display, you can select and
display the measurement individually and then check for a warning message.
Measurement warnings
The following measurement w arnings can be generated by the instrument. They may be generated in
various situations such as those described below. In general, measurement warnings produc e meas urement
results that are uncertain.
Warning Description
Not yet computed
Displayed until a measurement is completed. This is displayed if you hit the clear
button and the i nstrument is waiting for a trigger.
LT
GT
This is a measurement warning that’s only generated in some cases w here null
samples are present in a waveform, such as an ET waveform or a math waveform
generated by arbflt() functions. It is a warning that strictly speaking a measurement
might be larger then or less then the reported v alue because some samples were
null in measured waveform.
Uncertain
This is a generic warning regarding an uncertain result and can result for
measurements that depend on multiple sub-measurements to generate a result
(such as area, or rms that need to measure times and voltages). If one of the
sub-measurements generates a warning the combination of w arnings may be
combined to simply report ‘uncertain’ to the user.
Low signal amplitude
This is reported when the measurement system tries to fi nd a cross for a w aveform
less then 50 digitizing levels high.
Unstable histogram
This is generated for histogram measurements when the resulting histogram size
is too narrow to perform an accurate measurement. It might show up for some eye
measurements.
Low resolution
This is a common warning that can occur when there is insufficient horizontal
resolution to get accurate timing measurements.
Uncertain edge
This warning is generated in eye diagram measurements when there isn’t sufficient
resolution to determine an edge to measure.
Clipping positive
Clipping negative
Clipping pos neg
These are generated in response to any input waveform that has generated an over
range or under range DA C value, indicating the waveform went off screen.
xxx
740 DSA/DPO70000D, MSO/DPO/DSA70000C, DPO7000C, and MSO/DPO5000 Series
To Next Page
Loading...
Need help?
General
